Methods and apparatus enabling advanced and adaptive wireless transmit/receive unit (wtru) tracking for next generation mobile systems

A network function (NF) in a core network, wherein the NF is configured with NF tracking and reachability (TR) capabilities, the NF configured to:

• receive WTRU TR capabilities of a first WTRU, wherein the WTRU TR capabilities include capability of tracking from an alternate source;
• send, to the first WTRU, based on the WTRU TR capabilities and the NF TR capabilities, WTRU TR configuration, wherein the WTRU TR configuration includes identification of an alternate source of WTRU tracking information;
• send, to the alternate source of WTRU tracking information, a request for tracking information associated with the first WTRU;
• receive, from the alternate source of WTRU tracking information, tracking information associated with the first WTRU.

A method performed by a wireless receive and transmit unit (WTRU), the method comprising:

• sending, to a network, WTRU tracking and reachability (TR) capabilities;
• receiving, from the network, in response to sending the WTRU TR capabilities, WTRU TR configuration, wherein the WTRU TR configuration includes identification of an alternate source of WTRU tracking information and a condition to trigger the WTRU to provide tracking information to the alternate source of WTRU tracking information;
• and
• sending, to the alternate source of WTRU tracking information, based on determining that the condition is met, WTRU tracking information.